Tracer, clamp, and object engager for holding and tracing a lens mount of an eyeglass frame, a lens, and/or a lens pattern, to reliably detect a shape thereof even when the shape includes high wrap

ABSTRACT

A tracer is provided for tracing a lens mount of an eyeglass frame, a lens or a lens pattern. The tracer comprises an object engager and an actuator. The object engager is adapted to engage the lens mount, the lens or the lens pattern. The actuator is adapted to move the object engager into contact with and then along the lens mount, the lens or the lens pattern in such a way that during movement therealong, the object engager remains against the object being traced even when the shape thereof includes high wrap. Preferably, the tracer has a shift mechanism adapted to shift the object engager from alignment with the lens mount to alignment with a second lens mount of the eyeglass frame. The actuator preferably is further adapted to trace the second lens mount in substantially the same way as the first. The actuator further includes a rotator and a pivot mechanism. The rotator is adapted to rotate the object engager along the object being traced. The pivot mechanism facilitates movement of the object engager toward or away from the axis as the object engager is actuated along the object. The object engager can extend or retract along the pivot mechanism. A clamp for the tracer and an object engager also are provided.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a tracer, clamp, and objectengager for holding and tracing a lens mount of an eyeglass frame, alens, and/or a lens pattern, to reliably detect the shape thereof evenwhen the shape includes high wrap. The term “high wrap” as used hereinencompasses shapes that have a curvature greater than 6 diopters.Typically, though not necessarily, the high wrap is provided so that theeyeglass frame more closely follows the contour of the wearer's face.

[0002] In the eyeglass industry, it desirable to provide lenses havingdifferent shapes and sizes to accommodate different sizes and shapes ofeyeglass frames. Generally, eyeglass lenses start out as blanks havingcertain optical properties designed to correct one or more defects in apatient's vision. It is unlikely, however, that every member of thepopulation having such vision defect(s) will agree on one size or shapeof eyeglass frame. For this reason, lens blanks are routinely subjectedto edge processing in an effort to adapt them to a selected size andshape of eyeglass frames.

[0003] This custom edge processing can be achieved using any one ofseveral conventional techniques. According to one such technique, eacheyeglass frame manufacturers provide lens patterns that fit within therespective lens mounts of those manufacturers' eyeglass frames. When apatient selects a particular style and size of frame, a lens blank whichhas been formed to correct that particular patient's vision defect isplaced in an edging apparatus along with the pattern or patternsprovided by the frame manufacturer. The edging apparatus then traces thepattern and removes material from the periphery of the lens blank inaccordance with the pattern. This process is analogous to conventionalkey duplication techniques. U.S. Pat. No. 5,158,422 to Wagner, assignedto the assignee hereof, discloses an example of such an edgingapparatus. Alternatively, the edger may be numerically controlled inorder to eliminate the need for patterns.

[0004] The conventional pattern-based technique, however, has certaindrawbacks associated with it. These drawbacks include, for example, thenumber of patterns which must be provided, the storage space requiredfor such patterns, and the difficulties which arise when the patternsbecome misplaced or when they are misaligned during tracing. Typically,one or more patterns must be provided for each different shape and/orsize of eyeglass frame. The amount of storage space required for suchpatterns increases as the choices in eyeglass frame sizes and shapesexpand. Therefore, while the conventional technique is generallyeffective, there remains a need for a more convenient arrangement.

[0005] In order to provide a more convenient arrangement, efforts weremade to eliminate or reduce the need for patterns by providing a tracingapparatus capable of tracing the lens mounts of eyeglass frames. Theresults of such tracings then were used to provide edging informationfor use in edging a lens blank. U.S. Pat. No. 4,724,617 discloses anexample of such a tracing apparatus. While such tracing of the frames isgenerally effective when the lens mounts in the eyeglass frames aresubstantially planar, problems are frequently encountered when theframes have a high wrap.

[0006] In particular, the stylus that performs the tracing inconventional tracers is generally biased in a radially outward directionto engage a groove in the lens opening or mount of the eyeglass frame.This radially outward biasing remains effective so long as the groove inthe lens mount extends in the same radially outward direction. Eyeglassframes with high wrap, however, tend to have grooves in the high wrapregion which extend obliquely (and which can even approach theperpendicular) with respect to the radially outward direction. There isconsequently a tendency for the stylus of the tracing apparatus to “fallout” of the groove as it enters the high wrap region.

[0007] This incompatibility between conventional tracers and frameshaving a high wrap is exacerbated by the effects of gravity when theframes are held in the typical substantially horizontal, downward-facingorientation. In that orientation, the high wrap generally causes thesides of the frames to extend upwardly. As the stylus enters the highwrap region and the groove in the frame gradually transitions to a moreupwardly extending orientation, gravity acts to pull the stylus down andout from the groove. The stylus therefore tends to “fall out” of thegroove, rendering the tracing completely inaccurate. Tracers which holdthe frames in a horizontal, downward-facing orientation therefore tendto be limited to use on substantially planar eyeglass frameconfigurations.

[0008] Eyeglass frames, however, are available in many different shapesand sizes. Recently, eyeglass frames with high wrap shapes have becomeeven more popular than before. There is consequently a need in the artfor a versatile eyeglass frame tracer capable of tracing the lens mountseven if the eyeglass frame has a high wrap shape.

[0009] There also is a need in the art for a tracer which can trace notonly lens mounts with high wrap, but also lens patterns and actuallenses with high wrap when such lens patterns and actual lenses are morereadily available to the operator than the eyeglass frames.

SUMMARY OF THE INVENTION

[0010] It is a primary object of the present invention to satisfy atleast one of the foregoing needs in the art and to alleviate at leastone of the foregoing problems by providing a tracer adapted to tracelens mounts of eyeglass frames even when such eyeglass frames have highwrap.

[0011] Another object of the present invention is to provide a clampassembly for eyeglass frames, which clamp assembly has clamp arms whichmove symmetrically with respect to a plane of symmetry located betweenthe clamp arms.

[0012] To achieve these and other objects, the present inventionprovides a tracer for tracing a lens mount of an eyeglass frame, a lens,or a lens pattern. The tracer comprises an object engager and anactuator. The object engager is adapted to engage the lens mount, thelens, or the lens pattern. The actuator is adapted to move the objectengager into contact with and then along the lens mount, the lens, orthe lens pattern in such a way that during movement along the lensmount, the lens, or the lens pattern, the object engager remains againstthe lens mount, the lens, or the lens pattern even when a shape thereofincludes high wrap.

[0013] Preferably, the tracer further comprises a shift mechanismadapted to shift the object engager from alignment with the right lensmount to alignment with the left mount of the eyeglass frame. Theactuator preferably is further adapted to move the object engager intocontact with and then along the second lens mount in such a way thatduring movement along the second lens mount, the object engager remainsagainst the second lens mount even when a shape thereof includes highwrap.

[0014] Preferably, the actuator includes a rotator and a pivotmechanism. The rotator is adapted to rotate the object engager along thelens mount or along an edge of the lens or the lens pattern. The pivotmechanism is adapted to pivot the object engager away from the axis ofrotation of the rotator, so that the object engager engages the bevelgroove of the lens mount or the edge of the lens or lens pattern. Thepivot mechanism also is adapted to facilitate movement of the objectengager toward or away from the axis as the object engager is actuatedalong the lens mount or the edge of the lens or the lens pattern.

[0015] The object engager preferably is extendable and retractable withrespect to the pivot mechanism. In addition, the actuator may furtherinclude an extension mechanism adapted to extend or retract the objectengager with respect to the pivot mechanism.

[0016] The present invention also provides a clamp assembly for holdingeyeglass frames. The clamp comprises opposed clamp arms that are linkedto one another so that movement of one of the clamp arms in a firstdirection causes a corresponding movement of the other of the clamp armsin an opposite direction.

[0017] The present invention also provides an object engager. The objectengager comprises a first surface oriented for contact with a lens mountof an eyeglass frame, a second surface oriented for contact with abeveled lens edge, and a third surface oriented for contact with a lenspattern. The first surface has a stylus projecting therefrom, whereasthe second surface has a groove adapted to receive the beveled lensedge.

[0018] The above and other objects and advantages will become morereadily apparent when reference is made to the following descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view of an assembled tracer according to apreferred embodiment of the present invention.

[0020]FIG. 2 is a perspective view of the tracer illustrated in FIG. 1with its top cover removed.

[0021]FIG. 3 is a perspective view of a clamp according to a preferredembodiment of the present invention.

[0022]FIG. 4 is a side elevational view of the tracer mechanism which isillustrated in FIGS. 1-2.

[0023] FIGS. 5-7 are top, front, and side views, respectively, of aholder according to a preferred embodiment of the present invention.

[0024]FIG. 8 is a rear perspective view of the tracer mechanismillustrated in FIG. 4.

[0025]FIG. 9 is a perspective view of a pivot mechanism and an objectengager according to a preferred embodiment of the present invention.

[0026]FIG. 10 is a side view of the object engager which is illustratedin FIG. 9.

[0027]FIG. 11 is a rear perspective view of a rotator according to apreferred embodiment of the present invention.

[0028]FIG. 12 is rear perspective view of a shift mechanism according toa preferred embodiment of the present invention.

[0029]FIG. 13 is a schematic diagram of a control circuit according to apreferred embodiment of the present invention.

[0030]FIG. 14 is a perspective view of a combined tracer/edger apparatusaccording to a preferred embodiment of the present invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0031]FIG. 1 illustrates a tracer 10 according to a preferred embodimentof the present invention. The tracer 10 is adapted to trace a lens mountor opening 11 of an eyeglass frame 30, a lens 61A (shown in FIG. 7), ora lens pattern 61B (also shown in FIG. 7). The tracer 10 preferablyincludes a top cover 12 with a visually pleasant appearance. The topcover 12 includes a control panel 14. The control panel 14 preferably isprovided at an ergonomically suitable angle on the housing 12.

[0032] The control panel 14 includes a display device 16 and a keypad18. Preferably, the display device 16 is an LCD display screen. Thekeypad 18 may include numeric (or alphanumeric) push-button keys 18A, atleast one function key 18B, and a set of screen select keys 18C whichare aligned with positions on the LCD display screen where userselectable information can be displayed. The present invention, ofcourse, is not limited to the preferred arrangement shown in FIG. 1. Thedisplay device 16, for example, could be implemented using atouch-sensitive screen, in which case some of the keys 18A-18C in theexemplary keypad 18 can be eliminated in favor of “virtual” keys on thetouch-sensitive screen. Still other alternative implementations of thecontrol panel 14 can be used in accordance with the present invention.

[0033] The top cover 12 preferably encases most of the movablecomponents of the tracer 10. This serves to protect users of the tracer10 from potential injury that might otherwise result from exposure tomoving parts. The top cover 12 also keeps loose objects from fallinginto the movable components and jamming the movable components.

[0034]FIG. 2 shows the tracer 10 with the top cover 12 removed. The topcover 12, when present, rests on a housing base 24. Extending verticallyfrom the housing base 24 are two lateral walls 26. The lateral walls 26support the movable components of the tracer 10. The movable componentsinclude, among other things, a clamp assembly 28 for holding any one ofa plurality of different eyeglass frames 30 (e.g., as shown in FIG. 1).

[0035] As illustrated in FIG. 3, a preferred embodiment of the clampassembly 28 has opposed clamp arms 32A,32B. The clamp arms 32A,32B arelinked to one another, so that movement of one of the clamp arms 32A ina first direction (e.g., up) causes a corresponding movement of theother clamp arm 32B in an opposite direction (e.g., down).

[0036] Each clamp arm 32A,32B is pivotally connected to at least one(and preferably both) of the lateral walls 26. A gear 34 preferably isconnected to each clamp arm 32A,32B. According the preferred embodiment,two such gears 34 are provided for each clamp arm 32A,32B. The gears 34are located at both lateral ends 36 of the clamp arms 32A,32B and areconnected thereto so that the gears 34 rotate whenever their respectiveclamp arms 32A,32B pivot with respect to the lateral walls 26. The gears34 at each lateral wall 26 are intermeshed so that pivoting of one ofthe clamp arms 32A,32B in the first direction causes the other clamp arm32B,32A to pivot in the opposite direction. The clamp arms 32A,32Btherefore remain substantially equidistant from a plane of symmetry 40(shown in FIGS. 2 and 3) located between the clamp arms 32A,32B. Whilewe prefer the use of gears 34 as part of the clamp assembly, belts,friction rollers, and the like could also be used.

[0037] Preferably, the clamp arms 32A,32B are pivotally biased towardone another. This biasing can be provided using a spring mechanism orany other suitable means for biasing elements toward one another. Sincethe movement of each clamp arm 32A,32B is linked to movement of theother clamp arm 32B,32A by the gears 34, the biasing also can beprovided by making the top clamp arm 32A heavier than the bottom clamparm 32B. Gravity therefore would urge the top clamp arm 32A down withmore force than the bottom clamp arm 32B. The clamp assembly 28therefore would be biased toward closure. The amount of biasingadvantageously can be modified by adjusting the weight of the clamp arms32A and/or 32B.

[0038] Preferably, at least one of the clamp arms 32A,32B includes aframe centering device 42, as best shown in FIG. 2. The frame centeringdevice 42 in the preferred embodiment is located on the bottom clamp arm32B and is adapted to engage and retain a nose portion 44 of theeyeglass frame 30 when the eyeglass frame 30 is suitably positioned inthe clamp assembly 28. The frame centering device 42 preferably isspring-loaded to urge the frame centering device 42 into the noseportion 44 of the frame 30.

[0039] As illustrated in FIGS. 1-3, each of the clamp arms 32A,32Bpreferably includes at least one eyeglass frame support 46. In theillustrated embodiment, each clamp arm 32A,32B has two such framesupports 46. Each eyeglass frame support 46 has a notch 48 foraccommodating eyeglass frames 30. The notch 48 preferably has a V-shapedcross-section. The V-shaped cross-section of the notch 48 advantageouslyaccommodates frames of different thicknesses and, despite suchdifferences, tends to keep the frames 30 from moving within the notch48. In particular, the V-shaped cross-section cooperates with theaforementioned biasing of the clamp arms 32A,32B, to effectively centerthe frames at the apex 50 of the notch 48. The exemplary combination ofthe frame supports 46 and the frame centering device 42 serves to locatethe lens openings of the frames 30 laterally (side-to-side) with respectto the tracer 10 and at a predetermined distance from a front surface 52of the housing 12.

[0040] According to a preferred embodiment of the eyeglass framesupports 46, the supports 46 located on the top clamp arm 32A areattached to each other by a rocker arm which is pivoted at the center ofthe bar. This feature allows the two upper supports 46 to float relativeto each other, thereby accommodating frames that have eye openings thatvary in size by a small amount. The eyeglass frame supports 46,according to the preferred embodiment, may be coated with a softcompliant material to enhance clamping robustness.

[0041] Preferably, as illustrated in FIG. 3, the clamp assembly 28 isergonomically oriented to facilitate clamping and unclamping of eyeglassframes 30 by a human operator of the tracer 10. In particular, theexemplary embodiment of the clamp assembly 28 is oriented so that theframes 30 are received and held by the clamp assembly 28 at an angle ofabout zero to 45 degrees from a vertical orientation. As illustrated inFIG. 4, the eyeglass frames 30 preferably are held by the clamp assembly28 at an angle T of about 10 degrees from the vertical orientation V.

[0042] Since the clamp arms 32A,32B are linked so that movement of oneclamp arm 32A or 32B in one direction causes the other arm 32B or 32A tomove in the opposite direction, the angle T remains substantiallyconstant regardless of how far apart the clamp arms 32A,32B are whenthey engage the eyeglass frame 30. There is consequently little, if any,change in the angle T in response to variations in the size of theframes 30.

[0043] The small amount of tilt provided by the angle T is ergonomicallybeneficial because it aligns the eye openings in the eyeglass frame 30with the operator's typical line of sight S. This, in turn, facilitatesviewing of the positioning of the eyeglass frames 30 with respect to theclamp arms 32A,32B. It also facilitates use of a more direct arm motionwhen aligning and presenting the frames 30 to the clamp arms 32A,32B.

[0044] Arrangements that hold the frame 30 in a more horizontal thanvertical orientation, by contrast, make visualization of the alignmentmore difficult, because the user typically must bend over the tracer inorder to look down into where the frames 30 are held. Horizontalarrangements also tend to require more complicated (i.e., less direct)user arm motions when aligning and presenting the frames 30 to theclamping mechanism. The vertical or near-vertical orientation providedby the illustrated embodiment thus achieves significant ergonomicbenefits over the more horizontal orientations provided by otherdevices.

[0045] Inasmuch as certain situations may make tracing of a lens patternor an actual lens more practical or convenient than tracing of the frame30 itself, the present invention also provides a holder 60 for the lens61A or lens pattern 61B. A preferred embodiment of the holder 60 isillustrated in FIGS. 5-7. While both the lens 61A and lens pattern 61Bare shown in the drawings, it is understood that only one of them willbe held by the holder 60 during the tracing process.

[0046] The holder 60 includes legs 62 adapted to removably engagerespective ones of the clamp arms 32A,32B. The legs 62 preferably haverecessed ends 63 which are shaped to accommodated the clamp arms32A,32B. Alternatively, a snap-fitting or some other way of removablyengaging the legs 62 to the clamp arms 32A,32B can be used.

[0047] The holder 60 further includes a support 64 for the lens 61Aand/or for the lens pattern 61B. The support 64 is disposed between thelegs 62 of the holder 60, and is adapted to support the lens 61A or lenspattern 61B between the legs 62 without obstructing access to a bevelededge 66 of the lens 61A or to an edge 68 of the lens pattern 61B. Theedges 66,68 therefore remain unobstructed to facilitate tracing of them.

[0048] The lens 61A may be adhesively secured to a fastener using a LEAPpad 69. LEAP pads 69 are known in the industry to have two adhesivesides 69A,69B. One side 69A is applied to the optical center of the lens61 A and the other side 69B is applied to the head of the fastener(e.g., a bolt, screw, and the like). The fastener then is threadedlyreceived in a fastener tunnel 70 through the support 64. The lens 61Athereby can be fastened to the support 64.

[0049] The lens pattern 61B, by contrast, has a centrally disposedpassageway 72. The passageway 72 is adapted to receive the same or adifferent fastener, which fastener then is threadedly received in thefastener tunnel 70. In this manner, the lens pattern 61B may be fastenedto the support 64.

[0050] Preferably, at least one of the legs 62 has a recess 74 whichaccommodates one of the eyeglass frame supports 46 when the legs 62 areengaged with the clamp arms 32A,32B. Both legs 62 in the preferredembodiment have the recess 74. The preferred embodiment of the holder 60therefore accommodates two of the eyeglass frame supports 46.Preferably, the recesses 74, eyeglass frame supports 46, and the support64 of the holder are arranged so that engagement of the eyeglass framesupports 46 in the recesses 74 automatically aligns the support 64 in apredetermined tracing position. Any lens 61A or lens pattern 61B carriedby the support 64 therefore can be automatically aligned for tracing bythe mere act of placing the holder 60 between the clamping arms 32A,32Bso that the frame supports 46 are accommodated in the recesses 74. Thisadvantageously simplifies preparation of the tracer 10 for tracing ofthe lens 61A or lens pattern 61B.

[0051] With reference to FIGS. 4 and 8-10, the tracer 10 furtherincludes an actuator 83 and an object engager 84 adapted to engage thelens mount 11 (shown in FIG. 1) of the eyeglass frame 30, the lens 61A(shown in FIG. 7), or the lens pattern 61B (shown in FIG. 7). Parts ofthe actuator 83 have been omitted from FIG. 9 to permit bettervisualization of the object engager 84 and its relationship to theremaining parts of the actuator 83. The object engager 84 alone isillustrated in FIG. 10.

[0052] As illustrated in FIGS. 9 and 10, the object engager 84 includesa proximal end 85 and a distal end 86. The distal end 86, preferably,has features that permit the object engager 84 to more positively engagethe object being traced. Such features include, for example, a firstsurface 86A oriented for contact with the lens mount 11 and a secondsurface 86B oriented for contact with the beveled lens edge 66.

[0053] The first surface 86A preferably has a stylus 86C projectingtherefrom. The stylus 86C extends into the bevel groove of the framemount 11 while the frame mount 11 is being traced. Typically, the framemount 11 will have a bevel groove extending completely around the framemount's inner circumference. This groove generally is provided for thepurpose of receiving the beveled edge 66 of the lens 61A when the lens61A is mounted to the frame 30. During a tracing operation, however,there is no lens in the frame mount 11. The groove in the frame mount 11therefore is free to receive the stylus 86C.

[0054] In order to facilitate tracing of the lens 61A, as opposed to thelens mount 11, the second surface 86B of the distal end 86 has a groove86D which is adapted to receive the beveled edge 66 of the lens 61A.During the tracing operation, the aforementioned combination of theholder 60 and the clamp assembly 28 securely hold the lens 61A in place.Because the holder 60 is able to hold the lens 61A without obstructingaccess to the beveled edge 66, the beveled edge 66 may be kept in thegroove 86D as the second surface 86B moves around the entireouter-circumference of the lens 61A.

[0055] The second surface 86B also is oriented for contact with the lenspattern edge 68. Preferably, the second surface 86B further includes ashoulder 86E that engages the lens pattern edge 68. Like the lens 61A,the lens pattern 61B is held by the holder 60 without obstructing accessto the pattern edge 68. The pattern edge 68 therefore can remain againstthe shoulder 86E as the second surface 86B moves around the entire outercircumference of the lens pattern 61B.

[0056] Preferably, as illustrated in FIGS. 9 and 10, the second surface86B further includes a transition portion 86F located between the groove86D and the shoulder 86E. The transition portion 86F provides a bearingsurface along which the lens pattern edge 68 or the beveled lens edge 66may slide as the groove 86D is brought -into alignment with the beveledlens edge 66 or as the shoulder 86E is brought against lens pattern edge68. Preferably, as illustrated in FIGS. 9 and 10, the transition portion86F is saddle-shaped, the second surface 86B includes a bump 86G, andthe groove 86D is located at the peak of the bump 86G. The resultingarrangement, as will be described hereinafter, facilitates the processof initially locating the beveled edge 66 in the groove 86D, as well asthe process of initially locating the pattern edge 68 against theshoulder 86E.

[0057] The actuator 83 is adapted to move the object engager 84 intocontact with and then along the object being traced (i.e., the lensmount 11, the lens 61A or the lens pattern 61B). In particular, theactuator 83 is adapted to provide such movement along the object 11,61A, or 61B in such a way that the object engager 84 remains against theobject 11, 61A, or 61B even when the object 11 includes high wrap. Thisprovides a significant advantage over existing tracers which “fall out”of the lens mount 11 when they reach the high wrap region of theeyeglass frame 30.

[0058] The illustrated exemplary embodiment of the actuator 83 includesa rotator 90 adapted to rotate the object engager 84 along the lensmount 11 or along the beveled edge 66 of the lens 61A or the edge 68 ofthe lens pattern 61B. FIG. 11 illustrates the rotator 90 when the objectengager 84 and some of its associated components have been removed.

[0059] As shown in FIG. 11, the rotator 90 includes a rotatable plate90A, a set of rotatable guide rollers 90B, a rotation motor 90C, and apinion gear 90D connected to the output shaft 90E of the rotation motor90C. The rotation motor 90C preferably is reversible and has or isassociated with an encoder 90CC or other device capable ofelectronically communicating the output shaft's rotational position toan external device. The encoder 90CC advantageously can be implementedusing a rotary encoder, instead of a linear encoder. Rotary encoders cantypically be less expensive than linear encoders. The preferredembodiment therefore achieves a significant reduction in manufacturingcosts when compared to arrangements that require a linear encoder. Anysuitable means for determining the rotational orientation of plate 90Amay be utilized.

[0060] The pinion gear 90D rotates whenever the output shaft 90Erotates. The pinion gear 90D preferably meshes with a circumferentialgear 90F on the rotatable plate 90A. The rotatable plate 90A thereforealso rotates whenever the output shaft 90E of the motor 90C rotates.While the preferred embodiment provides direct coupling between thepinion gear 90D and the circumferential gear 90F, it is understood thatthe present invention is not limited to such arrangements. To thecontrary, indirect couplings, belt couplings, and the like can be usedwhen those arrangements become more desirable for one reason or another.The circumferential gear 90F likewise can be eliminated in favor of anyother suitable means for coupling the rotation of the output shaft 90Eto the rotatable plate 90A so that the rotatable plate 90A rotateswhenever the output shaft 90E rotates.

[0061] Preferably, the diameter of the plate 90A varies along itsthickness, and the circumferential gear 90F is located in a region ofincreased diameter. In the regions of less diameter than where the gear90F is located, the plate 90A presents a smooth circumferential surface90G. The smooth circumferential surface 90G makes contact with the guiderollers 90B. Preferably, the guide rollers 90B have a circumferentialrecess 90I that accommodates the gear 90F. The guide rollers 90B therebystraddle the gear 90F.

[0062] While the rotatable plate 90A is free to rotate, the plate 90A isprevented from shifting in a direction orthogonal to the rotation axis Rby the positioning of the rollers 90B. In addition, the increase indiameter of the plate 90A extends into the circumferential recesses 90Iof the rollers 90B to prevent the plate 90A from moving axially alongthe rotation axis R. Similar results can be achieved using alternativemeans, such as other roller configurations, different numbers andarrangements of rollers 90B, a shaft about which the plate 90A rotates,different bearing arrangements, and/or the like.

[0063] The guide rollers 90B are rotatably mounted to a back wall 95 ofthe actuator 83. A second rotatable plate 96 preferably is arrangedparallel to the first rotatable plate 90A. The second rotatable plate 96is connected to the first rotatable plate 90A by one or more braces 98.The braces 98 preferably extend parallel to the rotational axis R. Theback wall 95 has an aperture 99 that accommodates the braces 98 as theyextend from the first rotatable plate 90A to the second rotatable plate96. The combination of the first rotatable plate 90A, the secondrotatable plate 96, and the braces 98 defines a rotator cage 100 whichrotates in response to rotation of the motor's output shaft 90E.

[0064] The second rotatable plate 96 preferably is accommodated in anaperture 102 of a front wall 104 and is free to rotate in this aperture102. The front wall 104 may be secured to the back wall 95 by anysuitable means. In the illustrated embodiment, two beams 106 and a baseplate 108 connect the front wall 104 to the back wall 95.

[0065] As best illustrated in FIG. 4, the front and back walls 104,95may be tilted to angle T from vertical V. The front and back walls104,95 thus are substantially orthogonal to the line of sight S, andpreferably are parallel to the eyeglass frame 30 when the eyeglass frame30 is held by the clamp assembly 28.

[0066] As best shown in FIG. 11, rotatable plate 90A has a centralopening 110 and a radially extending slot 112. The combination ofcentral opening 110 and radially extending slot 112 allows the objectengager 84 to extend through the rotatable plate 90A, and therebypermits anchoring of the object engager 84 to the surface 1 14 of theplate 90A which faces away from the second rotatable plate 96.

[0067] The rotatable plate 90A further includes a counterweight 115. Thecounterweight 115 preferably is arranged so as to rotationally balancethe rotator 90. Since balancing of the rotator 90 will depend to someextent on the position of the object engager 84 (i.e., how much theobject engager 84 has been pivoted and how much it has been extended),the counterweight preferably is arranged to provide the desiredrotational balance when the object engager 84 is located at an averageor median tracing position. The rotator 90 therefore exhibits littletendency to rotate about the axis R toward a particular rotationalorientation when the object engager 84 is located in that average ormedian tracing position.

[0068] Because the actuator 83 includes electrical devices that requirepower and some of which send and receive signals to and from stationarydevices outside of the rotator 90, it is preferred that rotation of therotator 90 be limited to keep the wiring between such components frombecoming tangled, twisted, or damaged. The rotator 90 therefore includesa stop mechanism 116.

[0069] The stop mechanism 116 includes a stop bracket 118 which issecured to the back wall 95, and a stop arm 120 which is secured to therotatable plate 90A. The stop arm 120 extends radially out from therotatable plate 90A to engage a movable stop 122 in the stop bracket118. The stop bracket 118 holds the movable stop 122 (which preferablycomprises a ball, a roller, or the like) in a slot 124. The slot 124provides two slot walls 126. Each of the slot walls 126 (or one of theslot walls 126) has a groove 128 that accommodates part of the movablestop 122. The movable stop 122 is free to move through the bracket 118along groove(s) 128 but cannot move outside of the groove(s) 128.Preferably, the movable stop 122 is larger than the distance between thetwo slot walls 126. Movement of the stop 122 therefore terminates at thelongitudinal ends of the groove(s) 128. Groove(s) 128 preferably extendsabout 5 to 15 degrees about the rotational axis R (preferably, about 10degrees about the rotational axis R). When the 10-degree arrangement isutilized, rotation of the rotatable plate 90A is limited to a 370 degreerange.

[0070] With reference to FIG. 11, rotation of the plate 90A in acounterclockwise direction urges the movable stop 122 toward the right.When the movable stop reaches the right end of the groove(s) 128,counterclockwise rotation of the plate 90A terminates. The rotatableplate 90A, however, remains free to rotate in the clockwise direction.Such rotation, however, is limited to 370 degrees. In particular, whenthe plate 90A is rotated in the clockwise direction, the stop arm 120eventually returns to the bracket 118. As such rotation continues, themovable stop 122 is shifted to the left in the groove 128. When themovable stop 122 reaches the left end of the groove 128, clockwiserotation of the rotatable plate 90A terminates. The resulting shift ofabout 10 degrees in the position of the movable stop 122, thus, servesto limit rotation of the rotator 90 to a range of about 370 degrees.

[0071] The present invention, however, is not limited to the exemplarystop mechanism 116. To the contrary, there are numerous other ways tolimit the rotation of the rotator 90. Included in these other ways areelectrical control arrangements, motor controllers, and/or othermechanical stop mechanisms. Alternatively, the use of a stop mechanismcan be eliminated by providing wireless communication between theelectrical components that rotate along with the rotator 90, and thosethat are stationary, and/or by providing an arrangement of conductorsand brushes which maintain electrical contact with each other betweenthe rotator 90 and a stationary component, which electrical contact ismaintained irrespective of the rotational orientation of the cage 100.

[0072] In addition to the rotator 90, the actuator 83 also includes apivot mechanism 94, as best shown in FIG. 4, capable of pivoting theobject engager 84 toward or away from the rotation axis R so that theobject engager 84 initially engages the object being traced (i.e., thelens mount 11, the beveled edge 66, or the edge 68). Object engager 84is disposed at an angle of about 7.5° relative to the axis of rotation Rof cage 100 when in the rest position. After the initial engagement isachieved, tracing can begin. The pivot mechanism 94 therefore isadapted, according to the preferred embodiment, to facilitate movementof the object engager 84 toward or away from the rotation axis R as theobject engager 84 is actuated along the object being traced (i.e., alongthe lens mount 11, along the beveled edge 66, or along the edge 68).

[0073] The pivot mechanism 94 preferably is mounted in a pocket 134formed in the surface 114 of rotatable plate 90A. The pivot mechanism 94therefore rotates along with the rotatable plate 90A. With reference toFIGS. 8 and 9, the pivot mechanism 94 preferably includes two pivotbrackets 136 secured to the rotatable plate 90A. The pivot brackets 136,as illustrated in FIG. 8, are secured to the plate 90A on oppositessides of the radially extending slot 112. The pivot mechanism 94therefore extends through the radially extending slot 112, through thecage 100, and toward a diametrically extending slot 138 in the frontplate 104. Notably, the pivot axis P is offset from the rotational axisR. The amount of offset preferably is selected so as to maximize thecompatibility of the tracer 10 with different sizes and shapes of framemounts 11, lenses 61A, and lens patterns 61B. A preferred offset isbetween 25 and 30 millimeters, preferably about 27 millimeters.

[0074] Pivotally mounted between the pivot brackets 136 is a pivot arm140. Preferably, bearings 139 in the pivot brackets 136 facilitatepivoting of the pivot arm 140 with respect to the pivot brackets 136.The object engager 84 is carried by the pivot arm 140 and extendsthrough the diametrically extending slot 138. The object engager 84, byvirtue of its being carried by the pivot arm 140, is free to pivot alongwith the pivot arm 140 toward and away from the rotational axis R.

[0075] In order to control and/or detect such pivoting, the pivotmechanism 94 further includes a pivot motor 142, an output shaft 143 ofthe pivot motor 142, a pinion gear 144 connected to the output shaft 143for rotation therewith, and a curved pivot rack 145 that preferably isconnected to a distal end 146 of the pivot arm 140. The pivot motor 142preferably is reversible and has or is associated with an encoder 142Aor other device capable of communicating the output shaft's rotationalposition to an external device. The encoder 142A, much like the encoder90CC, can be implemented using a rotary encoder, instead of a linearencoder. Additional savings in manufacturing costs therefore can beachieved. Any suitable means for determining the pivotal position of thepivot arm 140 can be provided.

[0076] The pinion gear 144 rotates whenever the output shaft 143rotates. The pinion gear 144 preferably meshes with gear teeth 148 onthe pivot rack 145. The pivot rack 145 therefore causes pivoting of thepivot arm 140 whenever the output shaft 143 of the pivot motor 142rotates. In a similar manner, pivoting of the pivot arm 140 causes theshaft 143 to rotate. Rotation of the output shaft 143 therefore isindicative of pivoting of the pivot arm 140.

[0077] Preferably, the pivot rack 145 has a radius of curvature thatsubstantially matches the radial distance d, between the pivot axis P(shown in FIG. 9) and the curved pivot rack 145. This way, there is noneed to adjust the position of the pinion gear 144 during pivoting, noris there a need to pivotally connect the rack 145 to the pivot arm 140.The present invention, however, is not limited to arrangements havingmatched radii of curvature. The aforementioned alternatives to thepreferred embodiment may suffice, as may other arrangements capable ofpivoting the pivot arm 140 and/or capable of detecting the extent ofsuch pivoting.

[0078] While the preferred embodiment provides direct coupling betweenthe pinion gear 144 and the curved pivot rack 145, it is understood thatthe present invention is not limited to such arrangements. To thecontrary, indirect couplings, belt couplings, and the like can be usedwhen those arrangements become more desirable for whatever reason. Thecurved pivot rack 145 likewise can be eliminated in favor of any othersuitable means for coupling rotation of the output shaft 143 to pivotingof the pivot arm 140.

[0079] Preferably, after the object engager 84 is initially engaged withthe object to be traced, the pivot motor 142 applies a pivoting force tothe pivot arm 140, urging the pivot arm 140 toward the object beingtraced (e.g., the frame mount 11, lens 61A, or lens pattern 61B). Thispivoting force is maintained as the rotator 90 causes the pivotmechanism 94 to rotate. The object engager 84 therefore follows thecontour of the object being traced. During this process, the rotationalposition of the motor's shaft 143 is monitored (e.g., using encoder142A). In particular, sequential samples of the rotational position ofthe shaft 143 are taken. The collection of such samples is indicative ofhow much the pivot arm 140 has pivoted during each sample. Since thepivot arm 140 follows the contour of the object being traced, thecollection of samples provides information concerning the contour of theobject.

[0080] Often, however, the contour of the object (i.e., frame mounts 11,lenses 61A, and lens patterns 61B) will deviate from the radius ofcurvature defined by the predetermined distance d_(r). It is desirablein those situations to compensate for such deviations. The objectengager 84 of the preferred embodiment therefore is extendable andretractable with respect to the pivot mechanism 94. In particular, alinear bearing 150 (e.g., a linear ball slide) is disposed between theobject engager 84 and the pivot arm 140. The linear bearing 150 allowsthe object engager 84 to slide in order to compensate for deviations inthe radius of curvature by extending and retracting as needed, to keepthe object engager 84 in contact with the object being traced. This isespecially useful in connection with frames 30, lenses 61A, and/or lenspatterns 61B that are not symmetrical and those that have a high wrapfeature.

[0081] Preferably, an extension detector 164 is provided to detect howfar the object engager 84 has been extended with respect to the pivotarm 140. The resulting extension information then is communicated usinga suitable communication mechanism to a tracer controller and/or dataacquisition system, as will be described hereinafter. In the preferredembodiment, the extension detector is provided in combination with anextension mechanism 160. The extension mechanism 160 is adapted toextend or retract the object engager 84 with respect to the pivot arm140 of the pivot mechanism 94.

[0082] According to the preferred embodiment, the extension mechanism160 includes a linear rack 162 at the proximal end 85 of the objectengager 84, an extension motor 164, and a pinion gear 166 connected toan output shaft of the extension motor 164 for rotation therewith. Theextension. motor 164 preferably is reversible and has or is associatedwith an encoder 164A or other device capable of communicating the outputshaft's rotational position to an external device. Alternatively,suitable means for determining the amount of extension of the objectengager 84 can be provided. Because the encoder 164A can be implementedusing a relatively inexpensive rotary encoder, as opposed to a linearencoder, manufacturing costs can be Deduced according to the preferredembodiment.

[0083] The pinion gear 166 rotates whenever the output shaft of themotor 164 rotates. The pinion gear 166 preferably meshes with gear teeth170 on the linear rack 162. The linear rack 162 therefore causesextension or retraction of the object engager 84 whenever the outputshaft of the extension motor 164 rotates. In a similar manner, extensionor retraction of the object engager 84 (e.g., as the object engager 84traces the frame mount 11, lens 61A, or lens pattern 61B) causes theoutput shaft of the extension motor 164 to rotate. Rotation of theextension motor's output shaft therefore is indicative of the amount ofextension or retraction. This rotation, in turn, can be monitored usingthe encoder 164A.

[0084] While the preferred embodiment provides direct coupling betweenthe pinion gear 166 and the linear rack 162, it is understood that thepresent invention is not limited to such arrangements. To the contrary,indirect couplings, belt couplings, and the like can be used when thosearrangements become more desirable for whatever reason. The linear rack162 likewise can be eliminated in favor of any other suitable means forcoupling rotation of the output shaft of the motor 164 to extension orretraction of the object engager 84.

[0085] By monitoring rotation of the extension motor's output shaftduring the tracing operation, using the encoder 164A for example, it ispossible to determine how far the object engager 84 was extended duringseveral instances in the tracing process. The resulting samples then arecombined with the samples obtained from the pivot motor's encoder 142 toderive information about the contour of the object being traced.

[0086] Because the pivot arm 140 pivots to keep the object engager 84against the object being traced, and because the object engager 84 isextended and retracted as needed to keep the same part of the objectengager 84 in contact with the object, the collection of samples, whencorrelated with the rotational position of the rotator 90 at the instantthat each sample is taken, provides information concerning theconfiguration of that object, so that an accurate three-dimensionaltrace of the object can be recorded.

[0087] Notably, the preferred embodiment of the tracer 10 holds theobject (e.g., frame 30, lens 61A, or pattern 61B) being traced in avertical or near-vertical orientation. In FIG. 4, for example, the frame30 is tilted only about ten degrees from vertical. Gravitational force,therefore, has little or no component in the axial direction withrespect to the eyeholes or frame mounts 11 of the frame 30.

[0088] As a result, during the tracing operation, gravity provideslittle, if any, tendency for the object engager 84 to “fall out” of thelens mount 11 in a direction axial to the frame mount 11. Even when thestylus 86C engages the high wrap region of the lens mount 11, the forceapplied by gravity is not directed axially in such a way as to pull thestylus 86C out from the groove (not shown) in the lens mount 11.

[0089] Preferably, the curvature of the pivot rack 145, the dimensionsof the pivot arm 140 and object engager 84, and the orientation of theobject being traced are such that no “fall out” occurs when theface-form-curvature of the object ranges between 0 and about 10diopters. Thus, lens mounts 11, lenses 61A, and lens patterns 61B withface-form-curvatures above, for example, 6 diopters can be reliablytraced by the tracer 10 of the present invention, in addition to thosewith less face-form-curvature than 6 diopters.

[0090] Since each eyeglass frame 30 typically has two lens mounts 11,the tracer 10 preferably is adapted to shift the object engager 84 fromalignment with a first of the lens mount 11 to alignment with the otherlens mount 11 on the same eyeglass frame 30. This shifting can beaccomplished by moving the clamp assembly 28 that holds the eyeglassframe 30 and/or by moving the object engager 84 itself.

[0091] In the preferred embodiment of the tracer 10, the clamp assembly28 remains stationary while the object engager 84 is shifted. The tracer10 is provided with a shift mechanism 180 adapted to shift the objectengager 84 from alignment with one lens mount 11 to alignment with asecond lens mount 11 of the eyeglass frame 30. After this shifting isperformed, the actuator 83 moves the object engager 84 into contact withand then along the second lens mount 11 in substantially the same way asduring tracing of the first lens mount 11.

[0092] With reference to FIG. 12, the preferred shift mechanism 180includes an actuator support plate 182, guide rollers 184 which arerotatably mounted to the base plate 108, a shift rack 186, a shift motor188 having a rotatable output shaft 190, and a pinion gear 192 mountedfor rotation on the output shaft 190. The actuator support plate 182, asillustrated in FIG. 2, is secured to the lateral walls 26. The actuatorsupport plate 182 therefore remains stationary.

[0093] Notably, the actuator support plate 182 has outwardly bulginglateral edges 193. The outwardly bulging lateral edges 193 are receivedin correspondingly recessed circumferential surfaces 194 of the guiderollers 184. The bulging lateral edges 193, therefore, define a trackupon which the guide rollers 184 ride. Since the guide rollers 184 arerotatably mounted to the base plate 108, the entire actuator 83 ismovable along the length of the actuator support plate 182.

[0094] The pinion gear 192 is coupled to the shift rack 186. The shiftrack 186 is fixed to the actuator support plate 182. Thus, rotation ofthe pinion gear 192 causes movement of the actuator 83 along the lengthof the actuator support plate 182.

[0095]FIG. 12 illustrates the position of the shift mechanism 180 whenthe actuator 83 and the object engager 84 are aligned for tracing of theleft lens mount 11 (shown in FIG. 1) of the eyeglass frame 30. Aftertracing of the left lens mount 11 is completed, the motor 188 can beactivated to cause the pinion gear 192 to rotate. In particular, thepinion gear 192 in FIG. 14 is caused to rotate counter-clockwise. Sincethe actuator support plate 182 is held stationary by the lateral walls26, the pinion gear's rotation causes the actuator 83 to shift to theleft in FIG. 12. Such lateral shifting of the actuator 83 continuesuntil the base plate 180 comes into contact with an end stop 196. Theend stop 196 preferably is positioned along the length of the actuatorsupport plate 182 so that the base plate 108 contacts the end stop 196when the actuator 83 reaches a desired alignment for tracing of theright-side lens mount 11 of the eyeglass frame 30. Alternatively,sensors (not shown) can be used to determine when such shifting hasachieved predetermined positions along the length of the actuatorsupport plate 182.

[0096] The shift motor 188 preferably is reversible to facilitateshifting of the actuator 83 back toward the left-side lens mount tracingposition shown in FIG. 12. Another end stop 198 is provided on theactuator support plate 182. In particular, the other end stop 198 ispositioned along the length of the actuator support plate 182, so thatthe base plate 108 contacts the end stop 198 when the actuator 83reaches the desired alignment (shown in FIG. 12) for tracing of theleft-side lens mount 11 of the eyeglass frame 30. Preferably, the endstops 196,198 are positioned so as to permit lateral movement of theactuator 83 over a distance of about 64 millimeters, within a range of60-70 millimeters.

[0097] With reference to FIG. 1, the top cover 12 covers the actuator 83and most of the object engager 83 while the tracing operation is beingperformed. The top cover 12 includes elongated slots 200 through whichthe clamp arms 32A,32B extend. The clamp arms 32A,32B can pivot over arange defined by the length of the elongated slots 200. Preferably, thisrange is enough to permit tracing of frame mounts 11 and lenses 61Ahaving a diameter of as much as 78 millimeters.

[0098] The top cover 12 includes an oval opening 202. The oval opening202 exposes the second rotatable plate 96 through the top cover 12. As aresult, the diametrically extending slot 138 is exposed, and the objectengager 84 is able to extend through the housing 12. The longitudinaldimension of the oval opening 202 preferably is sufficient for the slot138 to remain completely exposed regardless of the positioning of theactuator 83 by the shift mechanism 180. The combination of rotary,pivotal, and translational actuation of an object engager 84 of thetracer 10 advantageously provides a tracer assembly which can be mademore compact than conventional linearly actuated tracers.

[0099] With reference to FIG. 113, the preferred embodiment of thetracer 10 is controlled by a control circuit 210. The control circuit210 preferably includes a processor core 212, a programmable logicdevice 214 (e.g., a CPLD (complex programmable logic device)), a displaysubsystem 216, a power switch 218, a pair of “RS-232” drivers 222,224,an Arcnet subsystem 226, and four motor drivers 228, 230, 234, 236. Thecontrol circuit 210 preferably is configured on a printed circuit board(PCB). The PCB may be mounted, for example, to the inside of the housing12, behind the keypad 18 and the display device 16. Connectors 213 canbe provided on the printed circuit board wherever it is desirable toconnect one of the circuit's components to an external device (i.e, adevice not on the PCB).

[0100] The power switch 218 is connectable to an external power supply238. When the switch 218 is closed, electrical power is supplied to theprocessor core 212. The processor core 212 preferably includes aprocessing unit 240 and a memory array 242. The processing unit 240includes, for example, an Intel 80C386EX chip with an {fraction (8/16)}bit external bus, a 32-bit internal bus, and two UARTs (universalasynchronous receiver/transmitters).

[0101] The memory array 242 preferably includes a program storage memory244, a system memory 246 which can be used for program data storage, anda non-volatile memory 248 for storage of calibration information,configuration information, and data gathered during tracing operations.The program storage memory 244 preferably is implemented using a flashmemory device capable of holding 256 kilobytes of 16-bit data. Thesystem memory 246 preferably is implemented using a SRAM memory devicecapable of holding 256 kilobytes of 16-bit data. The non-volatile memory248 preferably is implemented using; a serial flash memory devicecapable of holding 512 kilobytes of 8-bit data.

[0102] The software used to control the tracer 10 preferably is providedusing the “C” programming language, and wherever necessary, assemblylanguage programming. A Borland Turbo C v3.1 compiler can be used tocompile the source code. The preferred assembler is the TASM assemblerassociated with the aforementioned compiler. Paradigm Locate v6.0preferably is used as the linker/locator. The preferred operating systemis Custom Task Manager, and floating point math preferably isaccomplished using Software Emulation, as provided by Borland Turbo Cv3.1.

[0103] Preferably, the firmware system utilized by the control circuit210 is task-based. That is, all of the tracer operations preferably aredivided into different tasks. The tasks may operate on interrupts, atime slice or a combination of the two. The firmware system preferablyis set up as a cooperative multitasking system. Each task has to rununtil it completes, it is interrupted, or it surrenders control. Primarytask control is derived from a timer. The timer polls each time-slicedtask to see if it is ready for execution. The following is a list ofexemplary tasks: Motor Control: A. Shifting actuator 83 between left andright positions B. Locating the object engager 84 at a starting point onthe object being traced C. Tracing the frame 30 D. Tracing a lenspattern 61B E. Withdrawing the object engager 84 from the object beingtraced to a “home” position Measurement: A. Detecting amount of pivotingB. Detecting rotational orientation C. Detecting translational positionUser Interface: A. Keypad actuation B. Display C. Bar CodeCommunication: A. Arcnet B. RS-232 a. OMA b. National Optronics DataProcessing: A. Shape flattening B. Storing data C. Retrieving data D.Other calculations

[0104] Message handling, display updating, and data processingpreferably are performed on a periodic basis. The keypad-relatedfunctions, communication-related functions, encoder-related functions,and motor control functions, by contrast, are performed on anasynchronous basis, according to the preferred embodiment.

[0105] The processing unit 240 is connected to the memory array 242, thedisplay subsystem 216, the programmable logic device 214, the RS-232drivers 222,224, the Arcnet subsystem 226, and the motor drivers 228,230, 234, 236. The connection to the memory array 242 allows theprocessing unit 240 to store and retrieve data in and from the memoryarray 242. The connection to the Arcnet subsystem 226 facilitatescommunications (much like Ethernet communications) between theprocessing unit 240 and other devices linked to the Arcnet subsystem226. The Arcnet subsystem preferably includes a controller and a driver.

[0106] The connection to the RS-232 drivers 222,224 enables theprocessing unit 240 to communicate with external devices, such as anexternal bar code scanner 252. The display device 16 preferably iscontrolled indirectly by the processing unit 240 via the displaysubsystem 216. The display subsystem 216 includes a display controllerand memory, the combination of which is used to generate visualinformation on the display device 16.

[0107] The connection between the processing unit 240 and theprogrammable logic device 214 allows the processing unit 240 to receivesuitably conditioned data signals and interrupts from the programmablelogic device 214, which signals and interrupts are used by theprocessing unit 240 to appropriately carry out the desired tracingoperation(s).

[0108] The programmable logic device 214 receives user inputs from thekeypad 18 and is suitably programmed or otherwise configured to performaddress decoding and quadrature decoding, to control measurementinterrupts, and to control auxiliary input interrupts, based upon suchuser inputs and also based upon signals from the encoders 90CC, 142A,and 164A. The programmable logic device 214 therefore is connected tooutput signals from the keypad 18, from any auxilliary device 250, fromthe rotator motor's encoder 90CC, from the pivot motor's encoder 142A,and from the extension motor's encoder 164A.

[0109] In performing the address decoding function, the programmablelogic device 214 preferably provides select lines for all peripheraldevices. In performing quadrature decoding, the programmable logicdevice 214 converts encoder pulses from the encoders 90CC, 142A, and164A into a count. The programmable logic device 214, in the process ofperforming the quadrature decoding, also provides a parallel interfaceand decodes the direction of rotation for each of the motor's 90C, 142,and 164 based on the signals from the encoders 90CC, 142A, and 164A. Therotational position of the cage 100, the pivoting position of the pivotarm 140, and the translational position of the object engager 84therefore can always be known by the processing unit 240. Likewise, anappropriate PID servo control algorithm can be implemented to controlthe velocity and position of each motor 90C, 142, and 164.

[0110] In controlling the measurement interrupts, the programmable logicdevice 214 generates processor interrupts in response to gradient change(i.e., incremental changes in rotational orientation) and latches thecurrent position values for rotation, pivoting, and translation (i.e.,retraction or extension) based on the outputs from the encoders 90CC,142A, and 164A. With regard to the auxilliary data inputs, theprogrammable logic device 214 generates processor interrupts on edge,allows for the masking of inputs, and creates a register of digitalinputs.

[0111] The programmable logic device 214 preferably is programmed toscan input lines from the keys 18A-18C. When a key 18A-18C is pressed onthe keypad 18, the programmable logic device 214 responds by generatingan interrupt and latching data indicative of which key was pressed. Anindication of which key was pressed is thereby provided to processingunit 240 of the processor core 212.

[0112] Since the positioning of a predetermined contact area (e.g.,stylus 86C, groove 86D or shoulder 86E) of the object engager 84 can beexpressed in terms of polar coordinates, the various positions andmovements will be described hereinafter in terms of Theta, Radius, andZeta (or Z), wherein Theta designates the rotational orientation of thecage 100, Radius designates how far the contact area has been pivoted,if any, away from the rotational axis R, and Zeta (or Z) designates howfar the object engager 84 has been extended or retracted with respect tothe pivot arm 140. The encoders 90CC, 142A, and 164A in FIG. 13 aredenoted using the Theta, Radius, and Zeta designations.

[0113] The processing unit 240 preferably is suitably programmed orotherwise configured to perform a tracing operation on one or both ofthe lens mounts 11 of an eyeglass frame 30, to perform a tracingoperation on the lens 61A, and/or to perform a tracing operation on thelens pattern 61B. The processing unit 240 performs such tracingoperations by appropriately activating the motors 90C, 142, 162 (e.g.,via drivers 228, 230 and 234, respectively), by receiving samples ofpositional information from the encoders 90CC, 142A, and 164A duringsuch activation, and by converting the samples of positional informationreceived from the encoders 90CC, 142A, and 164A into informationsufficient to accurately represent the internal contour of the lensmount 11 and/or sufficient to accurately represent the external edge 66or 68 of the lens 61A or lens pattern 61B. The resulting informationthen is stored by the processing unit 240 in the memory array 242.Thereafter, this information can be communicated to an external devicevia one of the RS-232 drivers 222,224 or the Arcnet subsystem 226 and/orcan be displayed via the-display device 16.

[0114] The tracer 10 thus provides a position acquisition system adaptedto detect a translational position of the object engager 84 with respectto the pivot mechanism 94 and an angular position of the pivot mechanism94, for each of a plurality of rotational orientations of the objectengager 84. The memory array 242, in turn, provides an exemplary memorydevice which is connected, at least indirectly, to such a positionacquisition system and which also is adapted to store the translationalposition and the angular position for each of the plurality ofrotational orientations.

[0115] A preferred operation of the tracer 10 will now be described.Initially, the operator of the tracer 10 places the eyeglass frame 30 tobe traced in the clamp assembly 28. The configuration of the clampassembly 28 advantageously allows the operator to approach the tracer 10with the frame 30 in hand, bows open and held in an orientation as ifthe operator were going the place the frame 30 on his/her own face. Theframe 30 then is presented to the clamp assembly 28 by engaging thelower portion of the frame 30 into the eyeglass frame supports 46 on thebottom clamp arm 32B, while centering the nose portion 44 of the frame30 on the frame centering device 42. Once in this position, the frame 30is pushed down, thereby opening the clamp assembly 28 an amountnecessary to tip the top portion of the frame 30 into the eyeglass framesupports 46 on the top clamp arm 32A. The pushing is sufficient toovercome the bias toward closure which preferably is built-in to theclamp assembly 28. Once the top portion of the frame 30 is aligned withthe eyeglass frame supports 46 of the top clamp arm 32A, the operatorstops pushing downward on the frame 30. This, in turn, causes the clampassembly 28 to close in response to the aforementioned bias. Theeyeglass frame 30 thereby is held securely in place.

[0116] Since the clamp arms 32A,32B always remain equidistant from theplane of symmetry 40, the final, closed position of the clamp assembly28 places the vertical center of the frame mounts 11 at the plane ofsymmetry 40. Likewise, the position of the frame 30 in the horizontaldirection is centered automatically with respect to the oval opening 202by the frame centering device 42.

[0117] Before, during, or after clamping of the frame 30, information orqueries regarding operation of the tracer 10 may be displayed to theoperator using the display device 16 and/or the operator may enterinformation regarding the desired tracing operation via the keypad 18.The control circuit 210 responds to such information from the operatorby either requesting additional information or by initiating the tracingoperation.

[0118] The requests for additional information may include, for example,a requests for a Job Number, requests for information about the type oftrace desired (frame, lens, or lens pattern), requests for informationon which frame mount 11 or mounts 11 are to be traced (i.e., left mount,right mount, both mounts), requests for information about the type offrame being traced (e.g., metal, plastic, rimless, and the like), and/orrequests for information about whether the stored file is to beprotected.

[0119] While the preferred embodiment prompts the operator to enter suchinformation via the keypad 18, some of the foregoing requests can beeliminated by adapting the tracer 10 to automatically detect therelevant information. The request for the type of trace, for example,can be obviated by configuring the tracer 10 to detect whether a holder60 is present between the clamp arms 32A,32B instead of the frame 30.

[0120] The clamp arms 32A,32B, in this regard, may be electricallyinsulated from one another and the eyeglass frame supports 46 can bemade from electrically insulating material. If the holder 60 then ismade to exhibit a predictable electrical response to application of anelectrical signal, the presence of the holder 60 in the clamp assembly28 can be detected by applying such an electrical signal across theclamp arms 32A,32B and by making the tracer 10 responsive to theelectrical response. Other ways of detecting the relevant information,of course, can be provided.

[0121] After entry of any requested information, the control circuit 210automatically commences the tracing operation, or alternatively,commences the tracing operation only after the operator presses a STARTkey on the keypad 18.

[0122] At commencement of the tracing operation, the shift mechanism 160is automatically activated, if necessary, to shift the actuator 83 tothe appropriate side of the actuator support plate 182. In particular,this is accomplished by sending an appropriate “shift” signal from theprocessing unit 240 to the motor driver 236 which, in turn, causes themotor 188 to execute the requisite amount of rotation in the requisitedirection.

[0123] During the shifting operation, the object engager 84 preferablyremains fully retracted. The rotational axis R preferably lies in theplane of symmetry 40 associated with the clamp assembly 28. The shiftingoperation preferably is performed so as to substantially align thecenter of the lens mount 11 to be traced with the rotational axis R.

[0124] Before, during, or after shifting has been accomplished, therotator 90 is rotated so that the stylus 86C points toward either thetwelve-o-clock position (i.e., the orientation shown in FIG. 4) or thesix-o-clock position. The twelve-o'clock position will be usedhereinafter as an example. The six-o'clock position can be implemented,however, by reversing some of the following steps or orientations.

[0125] With the regard to the twelve-o'clock orientation, the processingunit 240 accomplishes the requisite rotation of the actuator 83 bysending an appropriate signal to the motor driver 228 which, in turn,causes the motor 90C to execute the requisite amount of rotation. Therotation is confirmed by the output from the encoder 90CC.

[0126] The object engager 84 then is extended along the rotational axisR. This trajectory is preferred because it brings the object engager 84into the frame mount 11 at the center thereof, and consequently reducesthe likelihood that the stylus 86C will collide with the frame mount 11during this initial movement. In order to achieve this initial movement,the processing unit 240 sends an appropriate signal to the motor driver234 which, in turn, causes the motor 164 to execute the requisite amountof rotation in the requisite direction. The processing unit 240 alsosends an appropriate signal to the motor driver 230 which, in turn,causes the motor 142 to execute a requisite amount of rotation in therequisite direction.

[0127] While such motor control commands can be sent simultaneously, apreferred arrangement provides rotation commands in an alternatingmanner, whereby incremental pivoting motions are interrupted byincremental extensions of the object engager 84. The combination ofincremental pivoting and incremental translational movements iscoordinated so that the stylus 86C moves along the rotational axis Runtil it reaches a predetermined position. This predetermined positioncan remain constant for all tracings and is defined as the positionwhere the distance between the stylus 86C and the pivot axis P issubstantially equal to the pivoting radius of the eyeglass frame support46 on the top clamp arm 32A.

[0128] The processing unit 240 then sends an appropriate signal to themotor driver 230, directing the motor driver 230 to activate the motor142. The motor driver 230 responds by causing the motor 142 rotate in adirection which causes the pivot arm 140 to pivot away from therotational axis R toward the frame support 46 on the top clamp arm 32A.The object engager 84 thereby is pivoted toward the lens mount 11.Preferably, the torque applied by the motor 142 during-such movement isenough to perform the requisite pivoting but is not enough to overcomethe bias provided by the clamp assembly 28 toward closure. Thus, whenthe lens mount 11 is reached by the stylus 86C, the stylus 86C does notpush the clamp assembly 28 open. Instead, the rotation of the motor 142stops and a signal to that effect is provided to the processing unit240, for example, by the encoder 142A associated with that motor 142.

[0129] The processing unit 240 then responds by commencing rotation ofthe cage 100. In particular, the processing unit 240 signals the motordriver 228 to commence rotation of the motor 90C in a first direction.The first direction of rotation will be such that the stop arm 120 movesaway from the movable stop 122. During such rotation, the motor 142continues to apply a pivoting bias away from the rotational axis R. Thispivoting bias keeps the stylus 86C engaged against the frame mount 11being traced.

[0130] As the rotation continues, variations in the shape of the lensmount 11 will cause the object engager 84 to extend and retract, and topivot toward and away from the rotational axis R. During such pivotingand translational movements of the object engager 84, the Theta encoder90CC is monitored. At predetermined intervals (preferably, at everygradient or 0.9 degrees of cage rotation), a “snapshot” is taken of theTheta, Radius, and Zeta positions based on signals from the Theta,Radius, and Zeta encoders 90CC, 142A, and 164A. Each “snapshot” resultsin a three-dimensional position vector. When the preferred interval ofone gradient is used, there are 400 such vectors for each revolution ofthe cage 100.

[0131] Theta, Radius, and Zeta values for each interval are suitablycaptured by the programmable logic device 214 and are supplied to theprocessing unit 240 for storage in the memory array 242. When the Thetaencoder 90CC indicates that an entire revolution has been completed, thecontrol circuit 210 determines whether the tracing operation is completeor whether the other lens mount 11 of the eyeglass frame 30 is to betraced.

[0132] If the other lens mount 11 is to be traced, the control circuit210 preferably directs the object engager 84 to return to the “home”position. The motor drivers 230 and 234 therefore cause the motors 142and 164 to return the object engager 84 to the fully retracted position,preferably parallel to or aligned with the rotational axis R.

[0133] The control circuit 210 then activates the shift mechanism 180 toshift the actuator 83 to the opposite side of the actuator support plate182. In the preferred embodiment, this is accomplished by sending anappropriate “shift” signal from the processing unit 240 to the motordriver 236 which, in turn, causes the motor 188 to execute the requisiteamount of rotation in the requisite direction. Thereafter, the secondframe mount 11 is traced in substantially the same way as the firstframe mount 11, except that the rotation of the cage 100 is in theopposite direction. The cage 100 thus returns to its originalorientation (the orientation before the first trace was performed) atthe end of the second trace. This reversal of the direction of rotationkeeps wires and the like which extend out from the cage 100 frombecoming twisted, stressed, or otherwise damaged. By arranging the stopmechanism 116 to permit a 370 degree rotation of the cage 110, one canensure that a full 360 rotation can be achieved, along withpre-measurement initiation or synchronization, in both rotationaldirections. After or during the second trace, the resulting data isstored in memory array 242.

[0134] The raw data stored in memory array 242 can be communicatedexternally, can be used to control a lens edger, and/or can be furtherprocessed by the processing unit 240. Several mathematical functions canbe carried out on the raw data to convert it into a form which is morecompatible with a lens edging apparatus. Examples of such functionsinclude but are not limited to curve fitting, curve smoothing, asperitycorrection, three-dimensional-to-two-dimensional flattening, sizeadjustment, and the like. Once such processing of the raw data isperformed, the converted data which results from such processing can bestored in an appropriate data file in the memory array 242 or can becommunicated to a device which is external to the tracer 10.

[0135] Removal of the frame 30 from the clamp assembly 28 after thetracing operation has been completed can be achieved by simply pushingup or down on the frame 30 and tipping the frame 30 out from the framesupports 46 as the clamp arms 32A,32B separate. The operator of thetracer 10 then can reset the control circuit 210 by pressing a key18A-18C on the keypad 18 which causes the display screen 16 to return tothe initial display (e.g. the display which requests “job” informationabout the desired trace from the operator).

[0136] If the tracing operation is to be performed on a lens 61A or lenspattern 61B instead of the frame 30, the operator of the tracer 10initially secures the lens 61A or lens mount 61B to the holder 60 in themanner indicated above with reference to FIGS. 5-7. The holder 60 thenis placed in the clamp assembly 28. The configuration of the clampassembly 28 advantageously allows the operator to approach the tracer 10with the holder 60 in a comfortable position and using a comfortablearm/hand motion.

[0137] The holder 60 is presented to the clamp assembly 28 by engagingthe lower leg 62 with the bottom clamp arm 32B. In doing so, the recess74 in the lower leg 62 is already aligned with one of the frame supports46 on the bottom clamp arm 32B. Preferably, in selecting which one ofthe two frame supports 46 on the bottom clamp arm 32B will be alignedwith the recess 74, the user chooses the frame support 46 which isaligned with the rotational axis R of the actuator 83. This, in turn,avoids any shifting of the actuator 83 which otherwise is required whenthe user selects the other frame support 46.

[0138] Once bottom leg 62 is suitably engaged with the bottom clamp arm32B so that the recess 74 receives the frame support 46, the holder 60is pushed down, thereby opening the clamp assembly 28 an amountnecessary to tip the top leg 62 into engagement with the top clamp arm32A. This top leg 62 likewise engages the top clamp arm 32A so that therecess 74 receives the upper frame support 46. The pushing is sufficientto overcome the bias toward closure which preferably is built-in to theclamp assembly 28.

[0139] Once the both recesses 74 receive respective frame supports 46while the legs 62 are held between the clamp arms 32A,32B, the operatorstops pushing downward on the holder 60. This, in turn, causes the clampassembly 28 to close in response to the aforementioned bias. The holder60 thereby is held securely in place.

[0140] Since the clamp arms 32A,32B always remain equidistant from theplane of symmetry 40, the final, closed position of the clamp assembly28 places the vertical center of the lens 61A or lens pattern 61B at theplane of symmetry 40. Likewise, the position of the holder 60 in thehorizontal direction is centered automatically with respect to therotational axis R by virtue of the recesses' alignment with the framesupports 46.

[0141] Before, during, or after clamping of the holder 60, informationor queries regarding operation of the tracer 10 may be displayed to theoperator using the display device 16 and/or the operator may enterinformation regarding the desired tracing operation via the keypad 18.The control circuit 210 responds to such information from the operatorby either requesting additional information or by initiating the tracingoperation.

[0142] The requests for additional information may include, for example,a requests for a Job Number, requests for information about the type oftrace desired (frame, lens, or lens pattern), requests for informationon which frame supports 46 have been placed in the recesses 74 of theholder 60, and the like. While the preferred embodiment prompts theoperator to enter such information via the keypad 18, some of theforegoing requests can be eliminated, as indicated above, by adaptingthe tracer 10 to automatically detect the relevant information.

[0143] After entry of any requested information, the control circuit 210automatically commences the tracing operation, or alternatively,commences the tracing operation only after the operator presses a STARTkey on the keypad 18.

[0144] At commencement of the tracing operation, the shift mechanism 180is automatically activated, if necessary, to shift the actuator 83 tothe appropriate side of the actuator support plate 182. As indicatedabove, this is accomplished by sending an appropriate “shift” signalfrom the processing unit 240 to the motor driver 236 which, in turn,causes the motor 188 to execute the requisite amount of rotation in therequisite direction.

[0145] During the shifting operation, the object engager 84 preferablyremains fully retracted. The shifting operation preferably serves toalign the center of the lens 61A or lens pattern 61B with rotationalaxis R.

[0146] Before, during, or after the shifting operation, the rotator 90causes rotation of the cage 100 so that the stylus 86C points toward thetwelve-o'clock position. This rotation, of course, is not necessary ifthe stylus 86C is already in that position. An alternativeimplementation involves arranging the stylus 86C to point toward thesix-o'clock position. In the following example, however, theimplementation using the the twelve-o'clock orientation will bedescribed.

[0147] Initially, the object engager 84 is pivoted to a predeterminedangle away from the rotational axis R and then is extended so that thetransition portion 86F of the object engager 84 is located radiallyoutside of the beveled edge 66 or edge 68. The predetermined angle isselected so that the object engager 84, when extended as far as thesupport 64 of the holder 60, is slightly closer to the rotational axis Rthan the radial distance separating the legs 62 of the holder 60 fromthe rotational axis R. Since the lens 61A, or lens pattern 61B is heldbetween the legs 62 of the holder 60, this selection of thepredetermined angle ensures that the transition portion 86F will belocated radially outside of the beveled edge 66 or edge 68. The objectengager 84 then is extended to an initial position which aligns thetransition portion 86F radially outside of the edge 66 or 68. The amountof initial extension is known because the distance between the support64 and the front surface 52 of the housing 12 is known and remainsconstant. The same amount of initial pivoting (Radius) and initialextension (Zeta) therefore can be used for all lenses 61A and lenspatterns 61B.

[0148] Upon achieving this initial positioning of the object engager 84,the processor 240, via the motor driver 230, causes the motor 142 topivot the object engager 84 toward the rotational axis R. Preferably,the torque applied by the motor 142 is enough to pivot the objectengager 84 but is not enough to overcome the bias toward closure of theclamp assembly 28. Thus, when the transition portion 86F comes intocontact with the beveled edge 66 or edge 68, rotation of the motor 142stops without opening the clamp assembly 28. The motor's stoppage iscommunicated to the programmable logic device 214 and processor core 212by the Radius encoder 142A. In response, the processing device 240determines that the transition portion 86F of the object engager 84 hasreached the beveled edge 66 or edge 68 of the lens 61A or lens pattern61B, respectively.

[0149] The next step depends on whether the object being traced is alens 61A or a lens pattern 61B. If a lens 61A is being traced, the motor142 continues to apply a slight biasing torque which biases the objectengager 84 toward the rotational axis R, and the motor 164 is activatedto retract the object engager 84. As a result of such retraction, thegroove 86D of the object engager 84 eventually reaches the beveled edge66, and the beveled edge 66 become lodged therein. The effect of thisengagement on rotation of the motor 164 is detected by the processingunit 240. The processing unit 240 determines based on this effect thatthe beveled edge 66 is properly engaged in the groove 86D.

[0150] If, by contrast, the object being traced is a lens pattern 61Binstead of a lens 61A, the next step after engagement of the transitionportion 86F to the edge 68 is to activate the motor 164 so as to extend(not retract) the object engager 84. This extension is accomplishedwhile applying substantially the same bias toward the rotational axis Ras is applied by the motor 142 in the case of a lens 61A. The objectengager 84 therefore slides along the edge 68 of the lens pattern 61Buntil the shoulder 86E reaches the edge 68. When the shoulder 86Ebecomes lodged against the edge 68 of the lens pattern 61B, rotation ofthe motor 164 stops. The effect of the shoulder 86E on rotation of themotor 164 is detected by the processing unit 240 (e.g., via Zeta encoder164A). The processing unit 240 then determines based on this effect thatthe edge 68 is properly engaged against the shoulder 86E. The processingunit 240 nevertheless keeps a slight amount of torque on the motor 164toward extension. This slight torque helps keep the shoulder 86E lodgedagainst the edge 68 of the lens pattern 61B.

[0151] Once the processing unit 240 determines that the shoulder 86E orgroove 86D has been engaged by the edge 68 or beveled edge 66,respectively, the processing unit 240 responds by commencing rotation ofthe cage 100. In particular, the processing unit 240 signals the motordriver 228 to commence rotation of the motor 90C in the aforementionedfirst direction. During such rotation, the motor 142 continues to applya pivoting bias toward the rotational axis R, and in the case of thelens pattern 61B, the motor 164 continues to apply the aforementionedbiasing toward extension. These biases keep the object engager's groove86D or shoulder 86E in contact with the beveled edge 66 or edge 68,respectively.

[0152] As the rotation continues, variations in the shape of the lens61A or lens pattern 61B will cause the object engager 84 to extend andretract, and to pivot toward and away from the rotational axis R. Duringsuch pivoting and translational movements of the object engager 84, theTheta encoder 90CC is monitored much like the Theta encoder is monitoredwhen a lens mount 11 is traced. At predetermined intervals (preferably,at every gradient or 0.9 degrees of cage rotation), a “snapshot” istaken of the Theta, Radius, and Zeta positions based on signals from theTheta, Radius, and Zeta encoders 90CC, 142A, and 164A. Each “snapshot”results in a three-dimensional position vector. When the preferredinterval of one gradient is used, there are 400 such vectors for eachrevolution of the cage 100.

[0153] Theta, Radius, and Zeta values for each interval are suitablycaptured by the programmable logic device 214 and are supplied to theprocessing unit 240 for storage in the memory array 242. When the Thetaencoder 90CC indicates that an entire revolution has been completed, thecontrol circuit 210 determines that the tracing operation for the lens61A or lens pattern 61B is complete.

[0154] Alternatively, if two lenses 61A or lens patterns 61B are to betraced, another holder 60 can be provided and mounted to the clampassembly 28 at the frame supports 46 which are not being used by thefirst holder 60. The processing unit 240, in that case, would bring theobject engager 84 back to the “home” position and would suitablyactivate the shift mechanism 180. The tracing process then would beperformed as described above, except that it would be performed at theother end of the oval opening 202.

[0155] The raw data gathered as a result of the tracing the lens 61A orlens pattern 61B can be stored in memory array 242 and can be used insubstantially the same way as the raw data which is provided aftertracing a frame 30 or frame mount 11 thereof. In particular, it can becommunicated externally, it can be used to control a lens edger, and/orit can be further processed by the processing unit 240. Mathematicalfunctions can be carried out on the raw data, as indicated above, toconvert it into a form which is more compatible with a lens edgingapparatus. The foregoing examples of mathematical functions apply alsoto the lens and lens pattern tracings, as do the post-conversionactivities described above.

[0156] Removal of the holder 60 from the clamp assembly 28 after thetracing operation has been completed can be achieved by simply pushingup or down on the holder 60 and tipping the holder 60 out from the clamparms 32A,32B as they separate. The operator of the tracer 10 then canreset the control circuit 210 by pressing a key 18A-18C on the keypad 18which causes the display screen 16 to return to the initial display(e.g. the display which requests “job” information about the desiredtrace from the operator).

[0157] The control circuit 210 of the tracer 10 preferably is suitablyprogrammed or otherwise configured to facilitate calibration of thetracer 10. In order for a trace to reflect the proper size, at leastsome initial form of calibration should be provided. This isaccomplished by tracing shapes of known size and then entering offset oradjustment values that are stored in the non-volatile memory 248.Whenever a trace is completed, these values are invoked so that theresulting data set accurately represents the item which was traced.Shapes of known size, whether frames, lenses or lens patterns, arecreated as hard tools and are mounted to the clamp assembly 28 in asimilar manner to the objects which are to be traced. A known frameshape can be created, for example, as a hole in a plate with a beveledgroove around the inside edge of the hole simulating the bevel groove ona frame. This shape may be a circle, ellipse, rectangle, or any othershape that can be traced and have its trace data compared to actualphysical measurements of the hole. Lenses and patterns are traced in asimilar manner by creating a “hard” lens or pattern of known shape anddimension and by mounting it to the same holder 60 that normal lensesand patterns are mounted to for tracing.

[0158] Once the calibration shape has been installed, the operatorenters a calibration command via the keypad 18. The control circuit 210responds by executing a calibration subroutine. In particular, thecontrol circuit 210 causes the tracer to execute a tracing operation onthe calibration shape. An estimated offset is entered via the keypad 18.Preferably, another trace is performed to check the result of the firsttest, and if further adjustment is needed, another entry is made. Thisiteration is performed until the size of the trace equals the dimensionof the calibration shape, at which time the calibration is complete. Thecalibration shape then can be removed and the tracer 10 can be used toperform a subsequent trace on an object of unknown dimensions.

[0159] The processing unit 240 preferably is suitably programmed orotherwise adapted to compensate for the effects of gravity duringrotation of the cage 100. The program stored in the memory array 242which enables the processing unit 240 to perform the tracing operation,in this regard, preferably includes a gravity compensation subroutine.This, however, is only one example of the various gravity compensationsystems which can be implemented in connection with the tracer 10.

[0160] The gravity compensation subroutine to some extent is associatedwith the pivot mechanism 94. It preferably counteracts the effects ofgravity on the angular position (Radius) of the pivot mechanism 94 bydirecting the processing unit 240 to adjust, via motor driver 230, thetorque applied by the motor 142 in keeping the object engager 84properly engaged to the object being traced (e.g., lens mount 11, lens61A, or lens pattern 61B). This adjustment of torque is performed in amanner dependent upon the rotational orientation of the object engager84 (i.e., in a manner dependent upon the rotational orientation of thecage 100). The biasing of the object engager 84 toward the object beingtraced therefore varies based upon the rotational orientation of theobject engager 84.

[0161] When the object engager 84 traces the lower part of the lensmount 11, for example, gravity alone provides enough biasing force thatthe torque of the motor 142 can be significantly reduced or eveneliminated. By contrast, when the top of the lens mount 11 is beingtraced, gravity tends to pull the object engager 84 away from the lensmount 11. The torque applied by the motor 142 therefore is increasedduring tracing of the top of the lens mount 11.

[0162] The opposite is true during tracing of the lens 61A or lenspattern 61B. When the lens 61A or lens pattern 61B is traced, thetracing is performed around the external circumference, as opposed tothe internal circumference. Gravity therefore tends to pull the objectengager 84 away from the lens 61A or lens pattern 61B when the bottom,not the top, of the lens 61A or lens pattern 61B is being traced.Likewise, when the top of the lens 61A or lens pattern 61B is beingtraced, gravity urges the object engager 84 toward the object beingtraced.

[0163] The gravity compensation system or subroutine therefore isresponsive not only to the rotational orientation of the cage 100 butalso to information concerning the object being traced, especiallywhether the object is a frame mount 11 on the one hand, or a lens 61A orlens pattern 61B on the other hand.

[0164] Since gravity also has a varying effect on translation of theobject engager 84 (i.e. retraction or extension) as the object engager84 rotates with the cage 100, the gravity compensation subroutinepreferably also provides compensation in the Zeta direction. Thiscompensation depends upon the orientation of the cage 100. It need notdepend, however, on the type of object being traced. The compensation inthe Zeta direction provided by the processing unit 240 in response tothe gravity compensation subroutine thus can be the same during tracingof a lens mount 11 as it is during tracing of a lens 61A or lens pattern61B.

[0165] The gravity compensation subroutine to some extent is associatedwith the extension mechanism 180. It preferably counteracts the effectsof gravity on the translational position (Zeta) of the extensionmechanism 180 by directing the processing unit 240 to adjust, via motordriver 234, the torque applied by the motor 164. In particular, thetorque is adjusted so as to counteract the weight of the object engager83 in the Zeta direction. The weight, however, varies as a function ofrotational orientation (Theta) and as a function of the pivotal position(Radius). The torque adjustment therefore is performed in a mannerdependent upon the rotational orientation of the object engager 84(i.e., in a manner dependent upon the rotational orientation of the cage100) and/or in a manner dependent upon how far the object engager 84 hasbeen pivoted from a horizontal orientation.

[0166] Since the pivoting angle (Radius) for most lens mounts 11, lenses61A, and lens patterns 61B will not deviate significantly from an“average” pivoting angle (Radius), the gravity compensation subroutinewhich compensates for the effect of gravity along the Zeta direction canbe simplified by causing the motor 164 to apply the compensation torquein a manner dependent only on the rotational orientation (Theta). Theaverage pivoting angle upon which the simplified subroutine is based canbe determined on a general basis (across all values of rotationalorientation (Theta)), or alternatively, it can be determined for eachrotational orientation (Theta) of the cage 100. It also can bedetermined individually for the category of objects being traced. Anaverage pivoting angle, in this regard, can be determined for lensmounts 11, another can be determined for lenses 61A, and yet another canbe determined for lens patterns 61B.

[0167] For each rotational orientation, therefore, the torque to beapplied by the motor 164 using the simplified gravity compensationsubroutine is determined based on what it would take to counteract theeffects of gravity at that particular rotational orientation when thepivot angle (Radius) equals the average (or median) value of pivot angle(Radius).

[0168] Regardless of whether gravity compensation is provided, thetracer 10 advantageously provides three-dimensional servo control to theextent that each axis is position encoded and capable of closed loopposition and/or force control via an appropriate servo algorithmimplemented using either software or firmware.

[0169] The left/right shifting which enables the tracer 10 to measureboth the left and right lens mounts 11 in an eyeglass frame 30, bycontrast, is not position-encoded and therefore is not closed loop servocontrolled. This, however, is not a limitation of the present invention,but rather a preferred embodiment which simplifies the construction ofthe left/right shifting mechanism 160.

[0170] Preferably, the processor core 212 is programmed to presentinteractive displays on the display device 16 before and during thetracing operation. The user of the tracer 10 is able to direct thetracer 10 to perform various tracing operations by selectively actuatingkeys 18A-18C on the keypad 18. The user then can review andappropriately respond to information and queries presented by thedisplay device 16. Any subsequent responses also can be entered usingthe same or other keys 18A-18C.

[0171] The processing unit 240 preferably is suitably programmed orotherwise configured to implement software algorithms adapted to handlefault conditions. One example is an algorithm adapted to determinewhether the object engager 84 has become disengaged from the objectbeing traced. This algorithm, for example, can be implemented based onwhether an erratic motion of the object engager 84 has been detected. Ifinformation from the encoders 90CC, 142A, or 164A, for example,indicates that the engagement has failed, an appropriate fault handlingalgorithm can be implemented in order to gracefully abort the tracingcycle and return the object engager 84 to the “home” position. Thealgorithm also can deliver an appropriate message or warning to theoperator via the display device 16, and can include with the messageinformation concerning what corrective action can be taken.

[0172] Once the tracing operation has been completed and the informationhas been converted and/or stored in memory array 242, the processor core212 can communicate the resulting trace information to an externaldevice, such as a remote data storage device, a remotely located orlocally provided lens and/or pattern edging machine, a modem, and/or acommunications network (e.g., a local area network (LAN), a telephonenetwork, and the like). Preferably, the information is communicated viaRS-232 driver 224.

[0173] An exemplary edging device 300 (the Optronics 6E Edger) which isbeing commercialized by the assignee hereof is illustrated in FIG. 14.Notably, the preferred embodiment of the tracer 10 can be nested on topof the exemplary edging device 300. By connecting the RS-232 driver 224to an appropriate input of the edging device 300, an integratededger/tracer apparatus can be provided, along with all the benefits ofthe tracer 10. The enhanced ability of the tracer 10 to trace framemounts, lenses and patterns having high wrap characteristics, forexample, provides an integrated edger/tracer which is advantageouslycapable of edging a lens so that the resulting lens will have thedesired high wrap configuration.

What is claimed is:
 1. A tracer for tracing a lens mount of an eyeglassframe, a lens or a lens pattern, said tracer comprising: an objectengager extending at an angle relative to the item to be traced andadapted to engage said lens mount, said lens, or said lens pattern; andan actuator adapted to move the object engager into contact with andthen along the lens mount, the lens, or the lens pattern in such a waythat during movement along the lens mount, the lens, or the lenspattern, the object engager remains against said lens mount, said lens,or said lens pattern even when a shape thereof includes high wrap. 2.The tracer of claim 1, further comprising a shift mechanism adapted toshift said object engager from alignment with said lens mount toalignment with a second lens mount of said eyeglass frame, said actuatorbeing further adapted to move the object engager into contact with andthen along the second lens mount in such a way that during movementalong the second lens mount, the object engager remains against saidsecond lens mount even when a shape thereof includes high wrap.
 3. Thetracer of claim 1, wherein said actuator includes: a rotator adapted torotate the object engager along the lens mount or along an edge of saidlens or said lens pattern; a pivot mechanism adapted to pivot saidobject engager away from an axis of rotation of said rotator so thatsaid object engager engages said lens mount or said edge of said lens orlens pattern, and also adapted to facilitate movement of said objectengager toward or away from said axis as said object engager is actuatedalong said lens mount or said edge of said lens or said lens pattern. 4.The tracer of claim 3, wherein said object engager is extendable andretractable with respect to said pivot mechanism.
 5. The tracer of claim3, wherein said actuator further includes an extension mechanism adaptedto extend or retract said object engager with respect to said pivotmechanism.
 6. The tracer of claim 3, farther comprising a clamp adaptedto hold said eyeglass frame.
 7. The tracer of claim 6, wherein saidclamp includes opposed clamp arms which are linked to one another sothat movement of one of said clamp arms in a first direction causes acorresponding movement of the other of said clamp arms in an oppositedirection, said movements of the clamp arms being substantiallysymmetrical with respect to said rotational axis.
 8. The tracer of claim7, wherein at least one of said clamp arms includes a frame centeringdevice adapted to engage and retain a nose portion of said eyeglassframe when the eyeglass frame is suitably positioned in said clamp fortracing of each lens mount.
 9. The tracer of claim 1, further comprisinga clamp adapted to hold said eyeglass frame.
 10. The tracer of claim 9,wherein said clamp includes opposed clamp arms which are linked to oneanother so that movement of one of said clamp arms in a first directioncauses a corresponding movement of the other of said clamp arms in anopposite direction.
 11. The tracer of claim 10, wherein at least one ofsaid clamp arms includes a frame centering device adapted to engage andretain a nose portion of said eyeglass frame when the eyeglass frame issuitably positioned in said clamp for tracing of each lens mount. 12.The tracer of claim 1, wherein said object engager has a first surfaceoriented for contact with said lens mount and a second surface orientedfor contact with said lens edge, said first surface having a stylusprojecting therefrom, whereas said second surface has a groove adaptedto receive a beveled lens edge.
 13. The tracer of claim 12, wherein saidsecond surface also is oriented for contact with a lens pattern edge andfurther includes a shoulder adapted to engage said lens pattern edge.14. The tracer of claim 13, wherein said second surface further includesa transition portion located between said groove and said shoulder, saidtransition portion providing a bearing surface along which said lenspattern edge or said beveled lens edge may slide as said groove isbrought into alignment with said beveled lens edge or as said shoulderis brought against said lens pattern edge.
 15. The tracer of claim 14,wherein said transition portion is saddle-shaped, said second surfaceincludes a bump, and said groove is located at a peak of said bump. 16.The tracer of claim 1, wherein: said actuator includes: a rotatoradapted to rotate the object engager along the lens mount or along anedge of said lens or said lens pattern; and a pivot mechanism adapted topivot said object engager away from an axis of rotation of said rotatorso that said object engager engages said lens mount or said edge of saidlens or lens pattern, and also adapted to bias said object engagertoward said lens mount or said edge of said lens or said lens pattern,said object engager being extendable and retractable with respect tosaid pivot mechanism so that said object engager follows the shape ofsaid lens mount, of said lens or of said lens pattern during rotation ofthe object engager, said tracer further comprising a positionacquisition system adapted to detect a translational position of saidobject engager with respect to said pivot mechanism and an angularposition of said pivot mechanism, for each of a plurality of rotationalorientations of said object engager.
 17. The tracer of claim 16, furthercomprising a memory device connected, at least indirectly, to saidposition acquisition system and adapted to store said translationalposition and said angular position for each of said plurality ofrotational orientations.
 18. The tracer of claim 16, further comprisinga gravity compensation system associated with said pivot mechanism forcounteracting the effects of gravity on said angular position, saidgravity compensation system being adapted to provide said biasing ofsaid object engager in a manner dependent upon the rotationalorientation of said object engager.
 19. The tracer of claim 1, wherein:said actuator includes: a rotator adapted to rotate the object engageralong the lens mount or along an edge of said lens or said lens pattern;a pivot mechanism adapted to pivot said object engager away from an axisof rotation of said rotator so that said object engager engages saidlens mount or said edge of said lens or lens pattern, and also adaptedto bias said object engager toward said lens mount or said edge of saidlens or of said lens pattern; and an extension mechanism adapted toextend or retract said object engager with respect to said pivotmechanism to achieve initial alignment of said object engager with saidlens mount, with said edge of said lens, or with said edge of said lenspattern, said object engager being extendable and retractable withrespect to said pivot mechanism so that said object engager follows theshape of said lens mount, of said lens or of said lens pattern duringrotation of the object engager, said tracer further comprising aposition acquisition system adapted to detect a translational positionof said object engager with respect to said pivot mechanism and anangular position of said pivot mechanism, for each of a plurality ofrotational orientations of said object engager.
 20. The tracer of claim19, further comprising a memory device connected, at least indirectly,to said position acquisition system and adapted to store saidtranslational position and said angular position for each of saidplurality of rotational orientations.
 21. The tracer of claim 19,further comprising a gravity compensation system associated with saidpivot mechanism for counteracting the effects of gravity on said angularposition, said gravity compensation system being adapted to provide saidbiasing of said object engager in a manner dependent upon the rotationalorientation of said object engager.
 22. The tracer of claim 21, whereinsaid gravity compensation system also is associated with said extensionmechanism to counteract the effects of gravity on said translationalposition, said gravity compensation system being adapted to counteractthe effects of gravity by also providing translational biasing of saidobject engager in a manner dependent upon the rotational orientation ofsaid object engager.
 23. The tracer of claim 1, further comprising: aclamp adapted to hold said eyeglass frame, wherein said clamp includesopposed clamp arms which are linked to one another so that movement ofone of said clamp arms in a first direction causes a correspondingmovement of the other of said clamp arms in an opposite direction; and aholder for said lens or said lens pattern, said holder having: legsadapted to removably engage respective ones of said clamp arms when saidlens or said lens pattern is to be traced instead of said lens mount;and a support for said lens or for said lens pattern, said support beingdisposed between said legs and adapted to support said lens or said lenspattern between said legs without obstructing access by said objectengager to a beveled edge of the lens or to an edge of the lens pattern.24. The tracer of claim 23, wherein each of said clamp arms includes atleast one eyeglass frame support with a notch for accommodating saideyeglass frame, each of said at least one eyeglass frame support beingpositioned so that placement of said eyeglass frame in said notch servesto align said lens mount for engagement by said object engager; andwherein at least one of said legs has a recess which accommodates one ofsaid at least one eyeglass frame support when said support for said lensor for said lens pattern is aligned with a substantial center of a rangeof motion of said object engager and said legs engage said respectiveones of said clamp arms.
 25. The tracer of claim 1, further comprising aclamp adapted to hold said eyeglass frame, wherein said clamp includesopposed clamp arms which are linked to one another so that movement ofone of said clamp arms in a first direction causes a correspondingmovement of the other of said clamp arms in an opposite direction;wherein each of said clamp arms includes at least one eyeglass framesupport with a notch for accommodating said eyeglass frame, each of saidat least one eyeglass frame support being positioned so that placementof said eyeglass frame in said notch serves to align said lens mount forengagement by said object engager.
 26. The tracer of claim 1, furthercomprising a clamp adapted to hold said eyeglass frame at apredetermined angle between 0 degrees and 45 degrees from a verticalorientation.
 27. The tracer of claim 1, wherein said clamp includesopposed clamp arms which are linked to one another so that movement ofone of said clamp arms in a first direction causes a correspondingmovement of the other of said clamp arms in an opposite direction, saidclamp being adapted to hold said eyeglass frame at a predetermined anglebetween 0 degrees and 45 degrees from a vertical orientation regardlessof how far apart said clamp arms are when they engage said eyeglassframe.
 28. A clamp for holding eyeglass frames, said clamp comprisingopposed clamp arms which are linked to one another so that movement ofone of said clamp arms in a first direction causes a correspondingmovement of the other of said clamp arms in an opposite direction. 29.The clamp of claim 28, further comprising at least one lateral wall,each clamp arm being pivotally connected to said at least one lateralwall, each clamp arm having a gear connected thereto which rotateswhenever said clamp arm pivots with respect to said at least one lateralwall, said gears being intermeshed so that pivoting of one of said clamparms in a first direction causes the other of said clamp arms to pivotin an opposite direction, whereby said clamp arms remain substantiallyequidistant from a plane of symmetry located between the clamp arms. 30.The clamp of claim 29, wherein said clamp arms are pivotally biasedtoward one another.
 31. The clamp of claim 30, wherein at least one ofsaid clamp arms includes a frame centering device adapted to engage andretain a nose portion of an eyeglass frame when the eyeglass frame issuitably positioned in said clamp.
 32. The clamp of claim 31, whereinsaid frame centering device is spring-loaded to urge said framecentering device into said nose portion.
 33. The clamp of claim 28,further comprising a holder for a lens or for a lens pattern, saidholder having: legs adapted to removably engage respective ones of saidclamp arms; and a support for said lens or for said lens pattern, saidsupport being disposed between said legs and adapted to support saidlens or said lens pattern between said legs without obstructing accessto a beveled edge of the lens or to an edge of the lens pattern.
 34. Theclamp of claim 33, wherein each of said clamp arms includes at least oneeyeglass frame support with a notch for accommodating an eyeglass frame;and wherein at least one of said legs has a recess which accommodatesone of said at least one eyeglass frame support when said support forsaid lens or for said lens pattern is located in a desired position. 35.The clamp of claim 28, wherein each of said clamp arms includes at leastone eyeglass frame support with a notch for accommodating said eyeglassframe.
 36. The clamp of claim 28, wherein said clamp arms are configuredto hold said eyeglass frame at a predetermined angle between 0 degreesand 45 degrees from a vertical orientation.
 37. The clamp of claim 28,wherein said clamp arms are adapted to hold an eyeglass frame at apredetermined angle between 0 degrees and 45 degrees from a verticalorientation regardless of how far apart said clamp arms are when theyengage said eyeglass frame.
 38. An object engager for a tracer, saidobject engager comprising: a first surface oriented for contact with alens mount of an eyeglass frame, and a second surface oriented forcontact with a beveled lens edge, said first surface having a stylusprojecting therefrom, whereas said second surface has a groove adaptedto receive said beveled lens edge.
 39. The object engager of claim 38,wherein said second surface also is oriented for contact with a lenspattern edge and further includes a shoulder adapted to engage said lenspattern edge.
 40. The object engager of claim 39, wherein said secondsurface further includes a transition portion located between saidgroove and said shoulder, said transition portion providing a bearingsurface along which said lens pattern edge or said beveled lens edge mayslide as said groove is brought into alignment with said beveled lensedge or as said shoulder is brought against said lens pattern edge. 41.The object engager of claim 40, wherein said transition portion issaddle-shaped, said second surface includes a bump, and said groove islocated at a peak of said bump.
 42. The method of tracing an eye mountof an eyeglass frame, comprising the steps of: securing the eyeglassframes in a substantially vertical orientation; curvalinearly extendingan object engager toward the eyeglass frames and thereby causing an endportion of the object engager to be seated within the bevel groove of afirst mount of the eyeglass frames; rotationally moving the objectengager about the bevel groove and collecting information about theconfiguration of the bevel groove; and determining the configuration ofthe bevel groove from the collected information.
 43. The method of claim42, including the step of: maintaining the object engager at an anglerelative to the axis of rotation.
 44. The method of claim 43, includingthe step of shifting the eyeglass frames laterally after the informationabout the configuration of the bevel groove has been collected andthereby exposing a second mount of the eyeglass frames.
 45. A lenstracer, comprising: first and second cooperating clamps adapted forholding an eyeglass frame therebetween, said clamps extending generallyhorizontally in order to vertically orient the eyeglass frame; anextensible object engager having a stylus for being seated within thebevel groove extending about a lens mount of a lens opening in theeyeglass frame; a rotatable cage, said object engager rotatable withsaid cage for thereby causing said stylus to trace about the bevelgroove, said object engager being angularly disposed relative to theaxis of rotation of said cage; and a plurality of encoders operablyassociated with said stylus and said cage for collecting informationindicative of the configuration of the bevel groove.
 46. The tracer ofclaim 45, wherein a shifter assembly is operable associated with saidclamps for linearly shifting the eyeglass frame in order to exposeanother lens mount after the information indicative of the configurationof said first mentioned bevel groove has been collected.